Irrigation probe for ablation during open heart surgery

ABSTRACT

An irrigation probe useful for ablation during open heart surgery is provided. The irrigation probe comprises a generally rigid probe body and a handle mounted to the proximal end of the probe body. The generally rigid probe body has an electrode at its distal end having at least one irrigation opening through which fluid can pass. An infusion tube extends through the probe body for introducing fluid to the electrode.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is a divisional of U.S. application Ser. No.09/692,494, filed Oct. 19, 2000, entitled IRRIGATION PROBE FOR ABLATIONDURING OPEN HEART SURGERY, which is a continuation-in-part of U.S.application Ser. No. 09/370,601, filed Aug. 10, 1999, the disclosures ofwhich are incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention is directed to an irrigation ablation probefor use during open heart surgery.

BACKGROUND OF THE INVENTION

[0003] Atrial fibrillation is a common sustained cardiac arrhythmia anda major cause of stroke. This condition is perpetuated by reentrantwavelets propagating in an abnormal atrial-tissue substrate. Variousapproaches have been developed to interrupt wavelets, including surgicalor catheter-mediated atriotomy. It is believed that to treat atrialfibrillation by radio-frequency ablation using a catheter, continuouslinear lesions must be formed to segment the heart tissue. By segmentingthe heart tissue, no electrical activity can be transmitted from onesegment to another. Preferably, the segments are made too small to beable to sustain the fibrillatory process.

[0004] It has been found that over 60% of patients with mitral valveproblems also have atrial fibrillation. Moreover, patients undergoingopen heart surgery commonly develop atrial fibrillation during thesurgery, and thus it would be useful to address this problem during thesurgery. Accordingly, under certain circumstances it may be desirable totreat atrial fibrillation during open heart surgery, for example, when apatient is undergoing a mitral valve replacement or repair procedure.Accordingly, a need exists for devices and methods for treating atrialfibrillation during open heart surgery.

SUMMARY OF THE INVENTION

[0005] The present invention is directed to an irrigation probeparticularly useful for treating atrial fibrillation during open heartsurgery. The probe of the present invention is also useful for otherablation and mapping procedures, particularly where irrigation of theablation site is desired, such as for treating ventricular tachycardia.The invention is also directed to novel methods for treating atrialfibrillation with the probe of the invention. In accordance with thepresent invention, the probe comprises a rigid probe body and anirrigation electrode, which provides cooling and irrigation in theregion of the tissue being ablated.

[0006] In one embodiment, the invention is directed to an irrigationablation probe comprising a generally rigid probe body having proximaland distal ends. The probe body has an electrode at its distal enddefining an inner cavity and having at least one irrigation openingthrough which fluid can pass and means for introducing fluid into theinner cavity. In a preferred embodiment, an infusion tube havingproximal and distal ends is in fluid communication with the innercavity. In another preferred embodiment, the infusion tube 36 extendsthrough the probe body for introducing fluid into the inner cavity ofthe electrode. In yet another preferred embodiment, the electrodecomprises an elongated body having first and second ends, which isfixedly attached, either directly or indirectly, to the distal end ofthe rigid probe body at a point along the elongated electrode bodybetween its ends, wherein the angle formed between the distal end of theprobe body and the electrode is greater than 0°. In still anotherembodiment, the electrode is attached generally perpendicular to thedistal end of the rigid probe body and has at least three irrigationopenings through which fluid can pass. In still yet another preferredembodiment the electrode comprises a flexible metal ribbon coiled aroundthe outside of a looped irrigation tube fixedly attached, eitherdirectly or indirectly, to the distal end of the rigid probe body, wherethe irrigation tube has irrigation openings through which fluid can passto the electrode and wherein the spaces between the coils provideopenings through which fluid can pass to the outside of the irrigationprobe.

[0007] In another embodiment, the invention is directed to an irrigationablation probe. The probe comprises a generally rigid probe body asdescribed above and a handle. The handle is mounted to the proximal endof the probe body. Ina preferred embodiment, the generally rigid probebody comprises a tubular body, an elongated electrode having first andsecond ends mounted to the distal end of the rigid probe body at a pointalong the elongated electrode body between its ends, wherein the angleformed between the distal end of the probe body and the electrode isgreater than 0°, and a non-conductive sheath covering the length of theprobe body. In still yet another embodiment the electrode comprises aflexible metal ribbon coiled around the outside of a looped irrigationtube fixedly attached either directly or indirectly to the distal end ofthe rigid probe body, where the irrigation tube has irrigation openingsthrough which fluid can pass to the electrode and wherein the spacebetween the coils provide openings through which fluid can pass to theoutside of the irrigation probe.

[0008] In another preferred embodiment, the generally rigid probe bodycomprises tubing having proximal and distal ends and at least one lumenextending therethrough. An electrode as described above is mounted atthe distal end of the tubing. The electrode has at least one irrigationopening through which fluid can pass. The probe body further comprisesmeans for introducing fluid through the irrigation opening(s) of theelectrode and a stiffening wire extending through a lumen of the tubing.A preferred means for introducing fluid comprises an infusion tube thatextends through a lumen of the tubing with the distal end of theinfusion tube in fluid communication with the at least one irrigationopening in the electrode. In one embodiment, an elongated electrodehaving first and second ends is mounted to the distal end of the rigidprobe body at a point along the elongated electrode body between itsends, wherein the angle formed between the distal end of the probe bodyand the electrode is greater than 0°. In a preferred embodiment theelectrode is fixedly attached, either directly or indirectly, generallyperpendicular to the rigid probe body and has at least three irrigationopenings through which fluid can pass. In another preferred embodiment,the electrode comprises a flexible metal ribbon coiled around theoutside of a looped irrigation tube fixedly attached either directly orindirectly to the distal end of the rigid probe body, where theirrigation tube has irrigation openings through which fluid can pass tothe electrode and wherein the space between the coils provide openingthrough which fluid can pass to the outside of the irrigation probe.

[0009] In still another embodiment, the invention is directed to amethod for treating atrial fibrillation in a patient. The methodcomprises opening the heart of the patient and ablating at least onelinear lesion in the heart tissue using an irrigation probe as describedabove.

DESCRIPTION OF THE DRAWINGS

[0010] These and other features and advantages of the present inventionwill be better understood by reference to the following detaileddescription when considered in conjunction with the accompanyingdrawings wherein:

[0011]FIG. 1 is a side view of an irrigation probe according to theinvention;

[0012]FIG. 2 is a side cross-sectional view of the handle of theirrigation probe of FIG. 1;

[0013]FIG. 3 is a perspective view of the distal end of the T-shapedirrigation probe of FIG. 1;

[0014]FIG. 4 is a side view of an alternative embodiment of anirrigation probe according to the invention;

[0015]FIG. 5 is a side cross-sectional view of the distal end of theflexible metal ribbon irrigation probe of FIG. 4, wherein the rigidprobe body comprises at least one lumen;

[0016]FIG. 6 is an end cross-sectional view of the distal end of theflexible metal ribbon irrigation probe of FIG. 4;

[0017]FIG. 7 is a side view of an alternative embodiment of anirrigation probe according to the invention; and

[0018]FIG. 8 is a perspective view of the distal end of the flexiblemetal ribbon irrigation probe of FIG. 7.

DETAILED DESCRIPTION

[0019] The present invention is directed to an irrigation probe for useduring open heart surgery. In one embodiment, as shown in FIGS. 1 and 2,the irrigation probe 10 comprises a probe body 12 mounted to a handle14. the probe body 12 comprises a tubular body 16, having proximal anddistal ends, covered over by a non-conductive covering or sheath 18along its length and an electrode 19 mounted at the distal end of thetubular body. The electrode 19 is a generally hollow tubular structurehaving two ends 20 and defining an inner cavity therein. The electrode19 is generally perpendicular to the tubular body 16 and fixedlyattached to the tubular body 16 at a point between the two ends 20 ofthe electrode. The junction of the tubular body 16 and the electrode 19forms an angle α that is greater than 0°, preferably greater than 10°,more preferably greater than 20°, even more preferably ranging from 70°to 110°, still more preferably ranging from 85° to 950. Still morepreferably, the electrode is fixedly attached at an angle α of about 90°relative to the distal end of the probe body, thus forming a generallyT-shaped arrangement. The tubular body 16 extends the entire length ofthe probe body 12, with the proximal end of the tubular body extendinginto the handle 14 as described in more detail below. The probe body 12preferably has a length (from the distal end of the handle to the distalend of the probe body) ranging from about 3.5 inches to about 12 inches,more preferably from about 5 to about 10 inches, still more preferablyfrom about 7 to about 8 inches.

[0020] The tubular body 16 and the electrode 19 are both made of amaterial that is generally rigid so that the probe body 12 cannot bendduring ablation, such as, for example, stainless steel (preferably304VSS) or nitinol. Preferably the tubular body 16 and the electrode 19have an inner diameter ranging from about 0.40 inch to about 0.90 inch,more preferably abut 0.047 inch, and an outer diameter ranging fromabout 0.50 inch to about 0.90 inch, more preferably about 0.059 inch. Ifdesire, the tubular body 16 and/or the electrode 19 can be heat-treatedso that they are malleable enough to be bent by a physician to a desiredshape but still rigid enough that they will not bend in use during aprocedure. For example, for 304VSS stainless steel, the material isheated to about 800° F. with electrical current or in a salt bath. Thehollow interior of the tubular body 16 forms a lumen through whichsaline and the like may be conducted to the inner cavity of theelectrode 19 by a separate external tube or the like.

[0021] The non-conductive sheath 18 extends from a proximal end insidethe handle 14 to a distal end at a union of the tubular body 16 and theelectrode 19. The sheath 18 can be made of any suitable biocompatiblenon-conductive material, such as polyurethane. In this arrangement, theelectrode is exposed, i.e., not covered by the sheath 18, for ablatingtissue, mapping, etc. Preferably, the length of the electrode 19 rangesfrom about 0.50 inch to about 1.5 inches, more preferably from about0.75 inch to about 1.25 inches.

[0022] In the depicted embodiment, the length of the probe body 12 isapproximately 7 inches. The proximal section of the probe body 12, i.e.,the portion extending from the handle 14, is approximately 5.5 inches.The length of the electrode 19, is approximately 1 inch.

[0023] As shown in detail in FIG. 3, the electrode 19 has a series ofirrigation openings 21 for passage of a cooling fluid out through theinner cavity of the electrode 19. The irrigation openings 21 can takeany suitable shape, such as rectangular or oval slots or round holes. Ina preferred embodiment the electrode 19 has at least three irrigationopenings 21. the irrigation openings 21 are preferably in the section ofthe electrode 19 that is to be in contact with the tissue during aprocedure, e.g., to enhance the cooling of an ablation site.

[0024] Saline or other suitable fluid is introduced into the innercavity of the electrode 19 through any suitable means. In the embodimentof FIGS. 1 to 3, fluids are introduced into the inner cavity of theelectrode 19 via the tubular body 16 through a luer hub 22 or the likeat the proximal end of the probe 10. The luer hub 22 is connected to aflexible plastic tubing 24, e.g., made of polyimide. The plastic tubing24 is attached, either directly or indirectly, to the proximal end ofthe tubular body 16, preferably within the handle 14, as shown in FIG.2. Alternatively, the tubing 24 can be connected to a suction source(not shown) to permit aspiration of fluid from the region of tissuebeing operated on.

[0025] As shown in FIG. 2, the handle 14 comprises a housing 26 having agenerally open interior 28. the tubular body 16 and sheath 18 extendinto the distal end of the handle housing 26. In the depictedembodiment, the sheath 18 terminated a short distance proximal to thedistal end of the housing 26. the tubular body 16 continues proximallybeyond the sheath 18. The flexible plastic tubing 24 extends into theproximal end of the handle housing 26. The plastic tubing 24 is attachedto the tubular body 16 within the open interior 28 of the handle,preferably at a point proximal to the proximal end of the sheath 18. Theplastic tubing 24 can be attached to the tubular body 16 by any suitablemeans, for example, polyurethane glue. By this design, cooling fluid isintroduced through the luer hub 22, thorough the plastic tubing 24,through the tubular body 16 and out the irrigation opening 21 in theelectrode 19.

[0026] Alternatively, fluid could be supplied to the electrode 19 andthereby the irrigation openings 21 via a separate irrigation tube (notshown) that can either run external to the tubular body 16 and attachdirectly to the electrode 19, or can extend through the tubular body 16to the electrode 19. In either case, this separate irrigation tube couldbe made of any suitable material, e.g., plastic or metal, and attach tothe electrode 19 by any direct or indirect means.

[0027] An electrode lead wire 30 having proximal and distal ends iselectrically connected at or adjacent its distal end to the probe body16. The proximal end of the lead wire 30 is attached to a connector 32for connection to a suitable source of ablation energy, e.g.,radio-frequency energy, or to an appropriate monitor. In the depictedembodiment, the lead wire 30 extends into the proximal end of the handlehousing 26. Within the open interior 28 of the handle 14, the distal endof the lead wire 30 is wrapped around the portion of the tubular body 16not covered by the sheath 18 and held in place by solder or the like.The portion of the lead wire 30 that extends outside the handle 14 iscovered by a flexible plastic protective tubing 34, e.g., made ofpolyimide.

[0028] An alternative embodiment of an irrigation probe according to theinvention is shown in FIGS. 4 to 6. As shown in FIG. 4, the probe 10comprises a probe body 12 and a handle 14. The probe body 12 comprises anon-conductive tubing 40 having proximal and distal ends. Inaparticularly preferred embodiment, the non-conductive tubing 40comprises outer and inner plastic walls, e.g., of polyurethane orpolyimide, surrounding an imbedded braided mesh of stainless steel orthe like. Preferably the tubing has an outer diameter or less than 8French, more preferably less than 7 French. The tubing 40 has threelumens 42, 44 and 46 extending along its length.

[0029] The irrigation probe comprises a metal ribbon electrode 47 at thedistal end 48 of the non-conducting tube 40 comprising an exposedmetallic ribbon 49 that is coiled around a loop of irrigation tubing 56,both of which are indirectly or directly fixedly attached to the distalend 48 of the non-conducting tube 40. as illustrated in FIG. 5, theprobe's distal end 48 is generally solid, having a fluid passage 50, afirst blind hole (not shown) and a second blind hole 54 that correspondin size and location to the three lumens 46, 42, and 44, respectively,in the non-conductive tubing 40. In the embodiment shown, the fluidpassage 50 is in fluid communication with the inner cavity of theflexible irrigation tube 56, which extends from the distal end of thefluid carrying lumen 46 out of the probes distal end 48. The irrigationtube 56 has a series of irrigation openings 57 for passage of a coolingfluid out through the spaces between the coils of the metallic ribbon49, as descried in more detail below. The irrigation openings 57 cantake any suitable shape such as rectangular or oval slots or roundholes. In a preferred embodiment, the irrigation tubing 56 has at leastthree irrigation openings 57. The irrigation openings 57 are preferablyin the section of the irrigation tubing 56 corresponding to the sectionof the metal ribbon electrode 47 that is to be in contact with thetissue during an ablation procedure to enhance the cooling to theablation site.

[0030] The metallic ribbon 49 is coiled loosely around the irrigationtube 56 such that fluid can pass unimpeded to the outside of the metalribbon electrode 47. the metal ribbon electrode 47, as shown in detailin FIG. 5, comprises a continuous ribbon 49 or conducting metal,extending outside of the probe's distal end 48 and coiled about theflexible irrigation tube 56 in a loop, having a radius ranging fromabout 0.5 inch to 1.5 inches. The metal ribbon 49 can be coiled in anymanner wherein the coils of the metal ribbon define an inner tubularpassage through which the irrigation tube 56 runs and wherein the coilsof metal ribbon 49 are generally spaced sufficiently far apart to allowfluid to escape through the irrigation passages. In a preferredembodiment, the metal ribbon electrode 49 is coiled around from 1% to100% of the length of the irrigation tube 56 that is outside the probebody 12. More preferably, the metal ribbon 49 is coiled around from 20%to 80% of the length of the irrigation tube 56, still more preferablythe metal ribbon is coiled around from 40% to 60% of the length of theirrigation tube 56. the metal ribbon 49 can be made of any suitablematerial, and is preferably machined from a 0.005 inch thick ribbon ofnitinol.

[0031] The metal ribbon 49 and the irrigation tube 56 can be attached tothe probe's distal end 48 in any suitable manner. In the depictedembodiment, the metal ribbon 49 and the irrigation tube 56 are eachattached at both ends to the probe's distal end 48 by a polyurethaneglue seal 58 or the like. However, any other means for fixedly mountingthe metal ribbon 49 and the irrigation tube 56 on the probe's distal end48 can also be used. For example, only one end of the metal ribbon 49and/or the irrigation tube 56 may be attached to the probe's distal end48.

[0032] The metal ribbon electrode 47 is connected to a lead wire 67having proximal and distal ends. The proximal end of the lead wire 67for the metal ribbon electrode 47 extends through the third lumen 46 oftubing 40 and through the handle 14. The distal end of the lead wire 67for the metal ribbon electrode 47 extends through the third lumen 46 andis attached to the metal ribbon electrode 47 by any conventionaltechnique, for example, by soldering.

[0033] In the embodiment shown, a mapping ring electrode 62 is mountedon the tubing 40 proximal to the probe's distal end 48. It is understoodthat the presence and number of ring electrodes may vary as desired. Thering electrode 62 is slid over the tubing 40 and fixed in place by glueor the lie. The ring electrode 62 can be made of any suitable material,and is preferably machined from platinum-iridium bar (90% platinum/10%iridium).

[0034] The ring electrode 62 is connected to a lead wire 64 havingproximal and distal ends. The proximal end of the lead wire 64 for thering electrode 62 extends through the first lumen 42 of tubing 40 andthrough the handle 14. the lead wire 64 can be connected to the ringelectrode 62 by any conventional technique. Connection of the lead wire64 to the ring electrode 62 is preferably accomplished by first making asmall hole through the tubing 40. such a hole can be created, forexample, by inserting a needle through the tubing 40 and heating theneedle sufficiently to form a permanent hole. The led wire 64 is thendrawn through the hole using a microhook or the like. The ends of thering electrode lead wire 64 are then stripped of any coating andsoldered or welded to the underside of the ring electrode 62, which isthen slid into position over the hole and fixed in place withpolyurethane glue or the like. Any other means for fixedly mounting thering electrode 62 to the tubing 40 can also be used.

[0035] Both lead wires 64 and 67 terminate at their proximal end in aconnector 32 that may be plugged into an appropriate monitor and/orsource of radio-frequency or other ablation energy. The portion of thelead wires 64 and 67 extending out the proximal end of the handle 14 areenclosed within a protective tubing 34, which can be made of anysuitable material, preferably polyimide, as shown in FIG. 4.

[0036] An infusion tube 72 is provided for infusing fluids, e.g.,saline, to cool the metal ribbon electrode 47 during ablation. theinfusion tube 72 may also be used to infuse drugs to the ablation site.The infusion tube 72 may be made of any suitable material, and ispreferably made of polyimide tubing. The infusion tube 72 has proximaland distal ends, with its distal end mounted in the fluid passage 50 ofthe probe's distal end 48 by any suitable method, e.g., by polyurethaneglue or the like. The infusion tube 72 extends from the probe's distalend 48, through the third lumen 46 of the tubing 40, and through thehandle 14. as would be recognized by one skilled in the art, the distalend of the infusion tube 72 can be positioned at any point within thethird lumen 46. the proximal end of the infusion tube 72 ends in a luerhub 22 or the like. Any other means for infusing fluids to the metalribbon electrode 47 can also be used, including running the infusiontube 72 external to the tubing 40 and fluid passage 50.

[0037] A stiffening wire 74, having proximal and distal ends, is mountedin the second lumen 44 of the tubing 40. the stiffening wire 74 is madeof a rigid metal or plastic material, preferably stainless steel, toprevent the probe body 12 from bending during a procedure. If desired,the stiffening wire 74 can be heat-treated so that it is malleable andcan be bent to a desired shape before use, but still rigid enough thatit will not bend in use during a procedure. A non-conductive tube 76,preferably made of polyimide, is attached to the distal end of thestiffening wire 74 for mounting the stiffening wire in the probe'sdistal end 48. the non-conductive tube 76 extends out of the secondlumen 44 and into the second blind hole 54 in the probe's distal end 48,and is secured in place by polyurethane glue or the like. Any othermeans for securing the stiffening wire 74 within the probe can also beused. The proximal end of the stiffening wire 74 terminates in thehandle 14 or near the proximal end of the probe body 12.

[0038] While FIGS. 4 to 6 depict an irrigation probe 10 having a metalribbon electrode 47, it will be understood that the irrigation probe 10described above and illustrated in FIGS. 4 to 6 could also house thegenerally T-shaped electrode 19 illustrated in FIGS. 1 to 3. In thisembodiment the generally T-shaped electrode 19 is fixedly attached,either directly or indirectly, to the probe's distal end 48 such thatthe fluid passage 50 is in fluid communication with the inner cavity ofthe generally T-shaped electrode 19. The construction and function ofthe lumens 42, 44 and 46, and the remainder of the probe 10 would besimilar to that described above and shown in FIGS. 4 to 6.

[0039] In another embodiment, as shown in FIGS. 7 and 8, the irrigationprobe 10 comprises a probe body 12 mounted to a handle 14, which isdescribed in detail above. The probe body 12 comprises a tubular body16, having proximal and distal ends, covered over by a non-conductivecovering or sheath 18. In this embodiment, a metal ribbon electrode 35comprising a coiled metal ribbon 33 and a loop of flexible irrigationtube 36 is disposed at the distal end of the probe body 12 and fixedlyattached, either directly or indirectly, to the distal end of thetubular body 16. The probe body 12 preferably has a length (from thedistal end of the handle to the distal end of the probe body) rangingfrom about 3.5 inches to about 12 inches, more preferably from about 5inches to about 10 inches, still more preferably from about 7 inches toabout 8 inches.

[0040] The tubular body 16 is made of a material that is generally rigidso that the probe body 12 cannot bend during ablation, such as, forexample, stainless steel (preferably 304VSS) or nitinol. Preferably thetubular body 16 has an inner diameter ranging from about 0.40 inch toabout 0.80 inch, more preferably about 0.047 inch, and an outer diameterranging from about 0.50 inch to about 0.90 inch, more preferably about0.059 inch. If desired, the tubular body 16 can be heat-treated so thatit is malleable enough to be bent by a physician to a desired shape butstill rigid enough that it will not bend in use during an ablationprocedure. The hollow interior of the tubular body 16 forms a lumenthrough which saline and the like may be conducted to the irrigationtube 36 of the metal ribbon electrode 35 and from there infused duringan ablation procedure, as described in more detail below. Alternatively,the tubular body 16 could be solid, in which case fluids could beintroduced into the irrigation tube 36 via a separate external tube orthe like.

[0041] The non-conductive sheath 18 extends from the proximal ends ofthe tubular body 16 inside the handle 14 to the distal end of thetubular body at the union of the tubular body 16 and the metal ribbonelectrode 35. The sheath 18 can be made of any suitable biocompatiblenon-conductive material, such as polyurethane. Preferably the diameterof the loop f the metal ribbon electrode 35 ranges from about 0.50 inchto 1.5 inches, more preferably from about 0.75 inch to about 1.25inches.

[0042] In the depicted embodiment, the length of the probe body 12 isapproximately 7 inches. The proximal section of the probe body 12, i.e.,the portion extending from the handle 14, is approximately 5.5 inches.The diameter of the loop of the metal ribbon electrode 35 isapproximately 1 inch.

[0043] As shown in detail in FIG. 8, the metal ribbon electrode 35comprise an irrigation tube 36 having first and second ends 37, at leaston e of which is fixedly attached either directly or indirectly to thetubular body 16, similar to the embodiment depicted in FIGS. 4 to 6. theirrigation tube 36 is bent so as to form a loop and the metal ribbon 33is in turn coiled around the irrigation tube 36 and fixedly attached,either directly or indirectly, to the tubular body 16. In one preferredembodiment, the metal ribbon 33 and irrigation tube 36 are both attachedto the tubular body 16 at both ends by any direct or indirect means,e.g., via a glue seal 38 as shown above in FIG. 5. Any other means forattaching the metal ribbon 33 and the irrigation tube 36 can also beused.

[0044] As shown, the irrigation tube 36 has a series of irrigationopenings 39 for passage of a cooling fluid out through the metal ribbon33. the irrigation openings 39 can take any suitable shape, such asrectangular or oval slots or round holes. In a preferred embodiment,shown in FIG. 8, the irrigation tube 36 has at least three irrigationopenings 39. the irrigation openings 39 are preferably in the section ofthe irrigation tube 36 corresponding to the section of the metal ribbon33 that is to be in contact with the tissue during a procedure, e.g., toenhance the cooling of the ablation site. The metal ribbon 33 is coiledloosely around the irrigation tube 36 such that fluid can pass unimpededthrough the metal ribbon 33.

[0045] Saline or other suitable fluid is introduced into the tubularbody 16 through a luer hub 22 or the like at the proximal end of theprobe 10. the luer hub 22 is connected to a flexible plastic tubing 24,e.g., made of polyimide. The plastic tubing 24 is attached, eitherdirectly or indirectly, to the proximal end of the tubular body 16,preferably within the handle 14, as shown in FIG. 7. By this design,cooling fluid is introduced through the luer hub 22, through the plastictubing 24, through the tubular body 16, through the first and secondends 37 of the irrigation tube 36 and out the irrigation openings 39.

[0046] The irrigation probe shown in various embodiments in FIGS. 1 to8, having either a metal ribbon electrode or a generally T-shapedelectrode, can be used in any manner in which a standard probe can beused. For example, the above described probes can be used during openheart surgery for ablation. During an ablation procedure, the heart isopened and the irrigated electrode is used to form continuous linearlesions by ablation. As used herein, a linear lesion refers to anylesion, whether curved or straight, between two anatomical structures inthe heart that is sufficient to block a wavelet, i.e., forms a boundaryfor the wavelet. Anatomical structures, referred to as “atrial triggerspots,” are those regions in the heart having limited or no electricalconductivity and are described in Haissaguerre et al., “SpontaneousInitiation of Atrial Fibrillation by Ectopic Beats Originating in thePulmonary Veins,” New England Journal of Medicine, 339:659-666 (Sep. 3,1998), the disclosure of which is incorporated herein by reference. Thelinear lesions typically have a length of from about 1 cm to about 4 cm,but can be longer or shorter as necessary for a particular procedure.

[0047] The probe described in FIGS. 1 to 3 having a long tubularelectrode is particularly useful for this procedure because it cancreate relatively long lesions. The probe depicted in FIGS. 4 to 6above, having a smaller but flexible ablation electrode, is useful ifthe surgeon does not want to ablate as much tissue or wants to ablate amore precise lesion. The above-described probe having a flexible body isparticularly useful if the surgeon needs to have a probe that conformsto a particular site to better ablate a desired region of tissue.Additionally, the flexible electrode is particularly useful for ablatinglocations where it is desirable to have the electrode conform to thetissue, rather than having the tissue conform to the electrode, forexample, an atrial appendage. Further, the circular coil design can beused to form a generally circular region around an orifice of a tubularstructure, such as a pulmonary vein, the coronary sinus, the superiorvena cava, or the inferior vena cava. Once the heart is closed, thesurgeon can use the probe on the outside of the heart, not only toablate, but to verify that the electrical conduction has been stoppedusing the mapping electrodes. As would be recognized by one skilled inthe art, the probes of the present invention can be used during openheart surgery for other procedures as well.

[0048] The preceding description has been presented with reference topresently preferred embodiments of the invention. Workers skilled in theart and technology to which this invention pertains will appreciate thatalterations and changes in the described structure may be practicedwithout meaningfully departing from the principal, spirit and scope ofthis invention.

[0049] Accordingly, the foregoing description should not be read aspertaining only to the precise structures described and illustrated inthe accompanying drawings, but rather should be read consistent with andas support for the following claims which are to have their fullest andfairest scope.

What is claimed is:
 1. An irrigation probe comprising: a generally rigidprobe body comprising: a generally rigid tubular body having proximaland distal ends, wherein the tubular body has at least one irrigationopening at its distal end through which fluid can pass to the innercavity of the irrigation tube, and a non-conductive sheath covering thetubular body; a generally flexible irrigation tube having first andsecond ends, the irrigation tube defining an inner cavity, wherein theirrigation tube generally forms a loop and at least one end is fixedlyattached to the distal end of the probe body, the irrigation tube havingat least one irrigation opening through which fluid can pass from theinner cavity to the outside of the irrigation tube; an electrodecomprising a flexible metal ribbon having first and second ends, whereinthe metal ribbon is coiled around the irrigation tube to form coils, andwherein space is provided between the coils to allow fluid to pass fromthe irrigation tube to the outside of the electrode; a handle mounted tothe proximal end of the probe body; and an infusion tube having proximaland distal ends, wherein the distal end of the infusion tube is in fluidcommunication with the inner cavity.
 2. An irrigation probe according toclaim 1, wherein the tubular body has an inner diameter ranging fromabout 0.40 inch to about 0.80 inch and an outer diameter ranging fromabout 0.50 inch to about 0.90 inch.
 3. An irrigation probe according toclaim 1, wherein the tubular body is made of a malleable material.
 4. Anirrigation probe according to claim 1, further comprising a flexibleplastic tubing attached to the proximal end of the tubular body forintroducing fluid into the tubular body.
 5. An irrigation probecomprising: a generally rigid probe body comprising: a tubing havingproximal and distal ends and first and second lumens extendingtherethrough, an infusion tube extending at least part of the waythrough the first lumen of the tubing, and a stiffening wire havingproximal and distal ends, the stiffening wire extending through thesecond lumen of the tubing; a generally flexible irrigation tube havingfirst and second ends, the irrigation tube defining an inner cavity,wherein the irrigation tube generally forms a loop and at least one endis fixedly attached to the distal end of the probe body, the irrigationtube having at least one irrigation opening through which fluid can passfrom the inner cavity to the outside of the irrigation tube; anelectrode comprising a flexible metal ribbon having first and secondends, wherein the metal ribbon is coiled around the irrigation tube toform coils, and wherein space is provided between the coils to allowfluid to pass from the irrigation tube to the outside of the electrode;and a handle mounted to the proximal end of the probe body; wherein theirrigation tube and the electrode are mounted at the distal end of thetubing of the probe body, and wherein the distal end of the infusiontube of the probe body is in fluid communication with the inner cavityof the irrigation tube.
 6. An irrigation probe according to claim 5,wherein the stiffening wire is made of a malleable material.
 7. Anirrigation probe according to claim 5, wherein the probe body has alength ranging from about 3.5 inches to about 12 inches.
 8. Anirrigation probe according to claim 5, wherein the probe body has alength ranging from about 7 inches to about 8 inches.
 9. A method fortreating atrial fibrillation in a patient comprising: opening the heartof the patient; and ablating at least one linear lesion in the hearttissue using an irrigation probe as recited in claim
 1. 10. A methodaccording to claim 9, wherein the tubular body has an inner diameterranging from about 0.40 inch to about 0.80 inch and an outer diameterranging from about 0.50 inch to about 0.90 inch.
 11. A method accordingto claim 9, wherein the tubular body is made of a malleable material.12. A method according to claim 9, further comprising a flexible plastictubing attached to the proximal end of the tubular body for introducingfluid into the tubular body.
 13. A method for treating atrialfibrillation in a patient comprising: opening the heart of the patient;and ablating at least one linear lesion in the heart tissue using anirrigation probe as recited in claim
 5. 14. A method according to claim13, wherein the stiffening wire is made of a malleable material.
 15. Amethod according to claim 13, wherein the probe body has a lengthranging from about 3.5 inches to about 12 inches.
 16. A method accordingto claim 13, wherein the probe body has a length ranging from about 7inches to about 8 inches.
 17. An irrigation probe comprising: agenerally rigid probe body comprising: a generally rigid tubular bodyhaving proximal and distal ends, wherein the tubular body has at leastone irrigation opening at its distal end through which fluid can pass tothe inner cavity of the irrigation tube, and a non-conductive sheathcovering the tubular body; a generally flexible irrigation tube havingfirst and second ends, the irrigation tube defining an inner cavity,wherein the irrigation tube generally forms a loop and at least one endis fixedly attached to the distal end of the probe body, the irrigationtube having at least one irrigation opening through which fluid can passfrom the inner cavity to the outside of the irrigation tube; anelectrode comprising a flexible metal ribbon having first and secondends, wherein the metal ribbon is coiled around from about 1% to 100% ofthe length of the loop formed by the irrigation tube, the metal ribbonforming coils, wherein space is provided between the coils to allowfluid to pass from the irrigation tube to the outside of the electrode;a handle mounted to the proximal end of the probe body; and an infusiontube having proximal and distal ends, wherein the distal end of theinfusion tube is in fluid communication with the inner cavity.
 18. Anirrigation probe according to claim 17, wherein the metal ribbonelectrode is coiled around from about 20% to about 80% of the length ofthe loop formed by the irrigation tube.
 19. An irrigation probeaccording to claim 17, wherein the metal ribbon electrode is coiledaround from about 40% to about 60% of the length of the loop formed bythe irrigation tube.
 20. An irrigation probe according to claim 17,wherein both ends of the irrigation tube are fixedly attached to thedistal end of the probe body.
 21. An irrigation probe according to claim20, wherein the first end of the irrigation tube is fixedly attached toa first position on the distal end of the probe body, and the second endof the irrigation tube is fixedly attached to a second position,different from the first position, on the distal end of the probe body.22. An irrigation probe comprising: a generally rigid probe bodycomprising: a tubing having proximal and distal ends and first andsecond lumens extending therethrough, an infusion tube extending atleast part of the way through the first lumen of the tubing, and astiffening wire having proximal and distal ends, the stiffening wireextending through the second lumen of the tubing; a generally flexibleirrigation tube having first and second ends, the irrigation tubedefining an inner cavity, wherein the irrigation tube generally forms aloop and at least one end is fixedly attached to the distal end of theprobe body, the irrigation tube having at least one irrigation openingthrough which fluid can pass from the inner cavity to the outside of theirrigation tube; an electrode comprising a flexible metal ribbon havingfirst and second ends, wherein the metal ribbon is coiled around fromabout 1% to 100% of the length of the loop formed by the irrigationtube, the metal ribbon forming coils, wherein space is provided betweenthe coils to allow fluid to pass from the irrigation tube to the outsideof the electrode; and a handle mounted to the proximal end of the probebody; wherein the irrigation tube and the electrode are mounted at thedistal end of the tubing of the probe body, and wherein the distal endof the infusion tube of the probe body is in fluid communication withthe inner cavity of the irrigation tube.
 23. An irrigation probeaccording to claim 22, wherein the metal ribbon electrode is coiledaround from about 20% to about 80% of the length of the loop formed bythe irrigation tube.
 24. An irrigation probe according to claim 22,wherein the metal ribbon electrode is coiled around from about 40% toabout 60% of the length of the loop formed by the irrigation tube. 25.An irrigation probe according to claim 22, wherein the first end of theirrigation tube is fixedly attached to a first position on the distalend of the probe body, and the second end of the irrigation tube isfixedly attached to a second position, different from the firstposition, on the distal end of the probe body.
 26. An irrigation probeaccording to claim 1, wherein both ends of the irrigation tube arefixedly attached to the distal end of the probe body.
 27. An irrigationprobe according to claim 1, wherein both ends of the irrigation tube arefixedly attached to the distal end of the probe body.
 28. An irrigationprobe according to claim 27, wherein the first end of the irrigationtube is fixedly attached to a first position on the distal end of theprobe body, and the second end of the irrigation tube is fixedlyattached to a second position, different from the first position, on thedistal end of the probe body.
 29. A method for treating atrialfibrillation in a patient comprising: opening the heart of the patient;and ablating at least one linear lesion in the heart tissue using anirrigation probe as recited in claim
 17. 30. A method for treatingatrial fibrillation in a patient comprising: opening the heart of thepatient, and ablating at least one linear lesion in the heart tissueusing an irrigation probe as recited in claim 22.